AN: so i am WAY behind actual canon, i've only seen the english aired episodes. This is just for the sake of writing fluff so enjoy what is probably wildly inaccurate fanfiction.
The daydreams. He didn't realize it when they started. He didn't even notice until they started to plague his mind through every waking moment. At first, he thought it was just his mind putting someone more 'obtainable' in the spot of Ladybug. Daydreams with the two of them cuddled by a fire, or running through the streets laughing together. They always were of him and Ladybug, until only recently. Slowly, without him even noticing, the image of her started to slowly morph into another familiar- albeit similar- face. Marinette. And now he was suddenly catching himself imaging himself leaning back during class, tilting his chair down and resting his head on the edge of her desk, and her leaning down and smiling at him. His daydreams were supposed to be of Ladybug, and only her! So why was he suddenly so invested in Marinette's words as she gave her class presentation on some old battle in French history? No one cared much about the project, yet she still seemed to capture his interest. Although he noticed that she had yet to make eye contact with him through her presentation, he still enjoyed listening to her explain this battles significance.
Slowly he started to lose her words along the way, and started to let his mind wander. When he came to the realization that his mind was now flooding with someone new, there was no hope in stopping it. The realization had only made it worse. At first, of course, he tried fighting it, since his heart belonged to his Lady and no one else. But as the days wore on, he started making more and more excuses for himself to think about Marinette. 'She's just really nice, is all', or 'It isn't staring if she's presenting, after all'. But as her image began to slowly replace Ladybug's, his excuses began to get weaker. He started to imagine what it would be like if she had more confidence around him, or what she would feel like to hug her. He imagined what it would be like if he was the one to help her get more confident, and to have her thank him for all of his help.
He sighed quietly as her presentation ended, trying his best to snap himself out of yet another daydream. But at the last second of her presentation, she glanced over, and made her first actual eye contact with Adrien of the entire presentation.
She has really pretty eyes…
And with that, his mind was off yet again, imagining staring into her eyes yet again.